Susceptor and substrate processing apparatus

ABSTRACT

A susceptor includes a plate part, a first heater for heating a first portion of the plate part, a second heater for heating a second portion of the plate part, and a heat insulating portion for thermally insulating the first portion and the second portion from each other on an upper surface side of the plate part.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a susceptor supporting a substrate and to a substrate processing apparatus provided with a susceptor.

Background Art

U.S. Pat. No. 6,469,283B1 discloses an arrangement for applying 100% of electric power to one region of a substrate supporting table having a plurality of regions and applying 50% of electric power to the other regions.

In some semiconductor or liquid crystal manufacturing processes, the temperature of a substrate is intentionally made uneven when the substrate is processed. For example, in some cases, film forming is performed on a substrate while the temperature of the substrate is made uneven, thereby making nonuniform the film thickness of a thin film formed on the substrate or making the film quality nonuniform. From the viewpoint of realizing such processing, it is preferable to create a definite temperature difference between certain different places in the substrate.

While the substrate supporting table disclosed in U.S. Pat. No. 6,469,283B1 is capable of separately heating the plurality of regions, the plurality of regions join one to another in the upper surface of the substrate supporting table. The substrate supporting table (susceptor) is generally made of a material having good heat conductivity, e.g., aluminum, aluminum nitride (AlN), carbon or silicon carbide (SiC). In the substrate supporting table disclosed in U.S. Pat. No. 6,469,283B1, therefore, transfer of heat from one zone to another is active and a definite temperature difference cannot be created between certain different places in a substrate.

SUMMARY OF THE INVENTION

In view of the above-described problem, an object of the present invention is to provide a susceptor capable of creating a definite temperature difference in a substrate and a substrate processing apparatus provided with the susceptor.

The features and advantages of the present invention may be summarized as follows.

According to one aspect of the present invention, a susceptor includes a plate part, a first heater for heating a first portion of the plate part, a second heater for heating a second portion of the plate part, and a heat insulating portion for thermally insulating the first portion and the second portion from each other on an upper surface side of the plate part.

According to another aspect of the present invention, a substrate processing apparatus includes a susceptor having a plate part, a first heater for heating a first portion of the plate part, a second heater for heating a second portion of the plate part, and a heat insulating portion for thermally insulating the first portion and the second portion from each other on an upper surface side of the plate part, a chamber in which the susceptor is housed, and an gas exhaust part attached to a side surface of the chamber, The first portion is a portion including an outer edge of the plate part, the second portion is a portion including an outer edge of the plate part, and the gas exhaust part and the first portion are opposed to each other as viewed in plan.

According to another aspect of the present invention, a substrate processing apparatus includes a susceptor having a plate part, a first heater for heating a first portion of the plate part, a second heater for heating a second portion of the plate part, and a heat insulating portion for thermally insulating the first portion and the second portion from each other on an upper surface side of the plate part, a chamber in which the susceptor is housed, and a gate valve attached to a side surface of the chamber. The first portion is a portion including an outer edge of the plate part, the second portion is a portion including an outer edge of the plate part, and the gate valve and the second portion are opposed to each other as viewed in plan.

Other and further objects, features and advantages of the invention will appear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a substrate processing apparatus according to a first embodiment;

FIG. 2 is a plan view of the plate part;

FIG. 3 is a diagram showing a method of controlling the temperature of the susceptor;

FIG. 4 is a diagram showing a substrate placed on the plate part;

FIG. 5 is a graph showing the temperature of the susceptor surface;

FIG. 6 is a plan view of the susceptor according to the second embodiment;

FIG. 7 is a plan view of the substrate processing apparatus according to the third embodiment;

FIG. 8 is a plan view of the substrate processing apparatus according to the fourth embodiment;

FIG. 9 is a sectional view of a susceptor and other members according to the fifth embodiment;

FIG. 10 is a sectional view of a susceptor according to the sixth embodiment;

FIG. 11 is a sectional view of a susceptor and other members according to the seventh embodiment; and

FIG. 12 is a sectional view of a susceptor according to the eighth embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A susceptor and a substrate processing apparatus according to an embodiment of the present invention will be described with reference to the drawings. Components identical or corresponding to each other are assigned the same reference numerals and repeated description of them is omitted in some cases.

First Embodiment

FIG. 1 is a sectional view of a substrate processing apparatus 10 according to a first embodiment of the present invention. The substrate processing apparatus 10 is constructed as a film forming apparatus for performing, for example, plasma enhanced atomic layer deposition (PEALD) on a substrate. The substrate processing apparatus 10 has a chamber (reactor chamber) 12. A radio frequency (RF) electrode 14 to which RF power is applied is provided in the chamber 12. Slits 14 a are provided in the RF electrode 14.

A susceptor 15 is provided in the chamber 12 so as to be opposed to the RF electrode 14. The susceptor 15 includes a plate part 16 and a slide shaft 18 supporting the plate part 16. The RF electrode 14 and the plate part 16 form a parallel plate structure.

A gas supply part 22 is connected to the RF electrode 14 with an insulating part 20 interposed therebetween. The gas supply part 22 is a part through which a material gas is supplied to a space between the RF electrode 14 and the susceptor 15. An exhaust duct 30 is provided between the RF electrode 14 and the chamber 12. The exhaust duct 30 is formed, for example, of a ceramic. An O-ring 32 suitably compressed is provided between the exhaust duct 30 and the RF electrode 14. An O-ring 34 suitably compressed is provided between the exhaust duct 30 and the chamber 12.

The exhaust duct 30 is formed into an annular shape as viewed in plan, such that it surrounds the plate part 16. An annular passage 30 b surrounding a processing space 17 on the plate part 16 is provided by the exhaust duct 30. In the exhaust duct 30, an annular slit 30 a through which a gas supplied into the processing space 17 is led into the annular passage 30 b and an exhaust port 30 c through which the gas in the annular passage 30 b is discharged to the outside are formed.

The exhaust port 30 c connects with a gas exhaust part 40 provided on a side surface of the chamber 12. The gas exhaust part 40 is provided to exhaust a material gas used for film forming. A valve 42 and a vacuum pump 44 are connected to the gas exhaust part 40. The pressure in the chamber 12 can be freely controlled by adjusting the exhaust rate with the valve 42 and the vacuum pump 44.

The thickness of the plate part 16 is, for example, 33 mm. It is preferable that the plate part 16 be formed of a material such as aluminum having good heat conductivity. In the plate part 16, a first heater 50 and a second heater 52 are embedded. The first heater 50 and the second heater 52 are each a resistance heater for example. A heat insulating portion 16A is provided between the first heater 50 and the second heater 52. The heat insulating portion 16A is a grooved portion in which a groove (gap) is provided. For the heat insulating portion 16A, a groove is provided in the upper surface of the plate part 16.

FIG. 2 is a plan view of the plate part 16. The diameter of the plate part 16 is set to, for example, 325 mm to support a substrate having a diameter of 300 mm. The plate part 16 has a central portion as a first portion 16 a. The first heater 50 is provided in annular form in the first portion 16 a. The first heater 50 is a heater for heating the first portion 16 a. The first heater 50 is indicated by a broken line. The first heater 50 has a center diameter of 180 mm for example. The center diameter is a value computed by dividing the sum of the outside diameter and the inside diameter by 2.

The plate part 16 has an outer portion as a second portion 16 b. The second heater 52 is provided in annular form in the second portion 16 b. The second portion 16 b surrounds the first portion 16 a as viewed in plan. The second heater 52 is a heater for heating the second portion 16 b. The second heater 52 is indicated by a broken line. The second heater 52 has a center diameter of 280 mm for example. The first heater 50 and the second heater 52 are provided concentrically with each other.

The heat insulating portion 16A is formed in annular form as viewed in plan. The heat insulating portion 16A is formed by a side surface of the first portion 16 a, a side surface of the second portion 16 b distanced from the side surface of the first portion 16 a and a bottom surface connecting these side surfaces. A groove 16A′ is provided by the heat insulating portion 16A. The heat insulating portion 16A functions as a heat insulating portion thermally insulating the first portion 16 a and the second portion 16 b from each other on the upper surface side of the plate part 16. The size of the groove 16′ is, for example, a width of 1.5 mm, a depth of 23 mm and a center diameter of 247.5 mm.

FIG. 3 is a diagram showing a method of controlling the temperature of the susceptor. The first heater 50 is connected to a heater controller 60 by wiring 50 a. The second heater 52 is connected to the heater controller 60 by wiring 52 a. The heater controller may be divided into two controllers for respectively controlling the first heater 50 and the second heater 52.

Wirings 50 a and 52 b are passed through the slide shaft 18 and extend to the outside from the lower end of the slide shaft 18. Therefore, the wirings 50 a and 50 b are not exposed to the interior of the chamber 12. If the wirings 50 a and 50 b are led from a side surface of the plate part 16 to the outside, the wirings 50 a and 50 b are exposed to the interior of the chamber 12 and subjected to plasma. Therefore, such a wiring layout is not preferable. Also, if the wirings 50 a and 50 b are led to the outside from a side surface of the plate part 16, there is a risk of the wirings 50 a and 50 b being damaged when the susceptor 15 is vertically moved. It is, therefore, preferable to lead out the wirings 50 a and 50 b from the lower end of the slide shaft 18.

A process module controller (PMC) 62 is connected to the heater controller 60. A unique platform controller (UPC) 64 is connected to the PMC 62. A temperature measuring part 65 for measuring the temperature of the susceptor 15 is attached to the plate part 16. The temperature measuring part 65 is, for example, a thermocouple. Information on the temperature measured with the temperature measuring part 65 is transmitted to a temperature controller 66. This information is used for control of the temperature of the susceptor 15.

A method of processing a substrate with the substrate processing apparatus 10 having the above-described susceptor 15 will be described. The vacuum pump 44 is constantly operated to maintain a vacuum in the chamber 12. A substrate to be processed is first placed on the plate part 16. FIG. 4 is a diagram showing a substrate 70 placed on the plate part 16. The substrate 70 is placed both on the first portion 16 a and on the second portion 16 b. The portion of the substrate 70 on the first portion 16 a is referred as a substrate central portion 70A. The portion of the substrate 70 on the second portion 16 b is referred to as a substrate marginal portion 70B. In the case of a substrate having a film such as SiO₂ film attached to its back surface, the film absorbs water and there is a possibility of the substrate sliding when placed on the heated susceptor. It is thus preferable to provide a shallow groove for receiving the substrate 70 in the upper surface of the plate part 16 to ensure that the substrate does not slide on the plate part 16. A small projection may alternatively be provided on the upper surface of the plate part 16, and the side surface of the substrate may be caused to abut against the projection in order to prevent the substrate from sliding.

Subsequently, the substrate 70 is heated. In a recipe in which conditions for processing the substrate 70 are described, a target temperature of the first portion 16 a and a target temperature of the second portion 16 b are set. The heater controller 60 energizes the first heater 50 and the second heater 52 based on this setting so that the first portion 16 a and the second portion 16 b has the target temperatures. For example, the first portion 16 a has a temperature of 300° C. and the second portion 16 b has a temperature of 305° C.

At this time the groove 16A′ functions as a heat insulating layer because the groove 16A′ has a vacuum therein. With the heat insulating portion 16A (groove 16A′), transfer of heat between the first portion 16 a and the second portion 16 b can be limited on the upper surface side of the plate part 16. That is, since the first portion 16 a and the second portion 16 b are thermally insulated from each other on the upper surface side of the plate part 16 by the heat insulating portion 16A, a definite temperature difference can be created on the upper surface side of the plate part 16.

FIG. 5 is a graph showing the temperature of the susceptor surface. A solid line indicates the surface temperature of the plate part 16 according to the first embodiment of the present invention. More specifically, the solid line indicates a temperature distribution along line A-A′ in FIG. 2. For the first portion 16 a, the temperature in accordance with the setting in the recipe (300° C.) was substantially realized. Also for the second portion 16 b, the temperature in accordance with the setting in the recipe (305° C.) was substantially realized. Moreover, the provision of the heat insulating portion 16A for thermally insulating the first portion 16 a and the second portion 16 b on the upper surface side of the plate part enabled creating a definite temperature difference between the first portion 16 a and the second portion 16 b.

On the other hand, a broken line in FIG. 5 indicates the temperature of a susceptor surface according to a comparative example. The susceptor according to the comparative example is generally the same as the susceptor according to the first embodiment of the present invention but differs in that the heat insulating portion is not provided. Since no heat insulating portion exists in the plate part of the susceptor according to the comparative example, heat transfers between the first portion (central portion) and the second portion (marginal portion) on the upper surface side of the plate part. Therefore, the temperature distribution in the susceptor surface in the comparative example is such that the temperature increases gradually along a direction from the center toward the outer edge of the plate part. That is, a definite temperature difference cannot be created in the plate part.

The definite temperature difference created in the plate part 16 according to the first embodiment is reflected in the temperature of the substrate 70 placed on the plate part 16. That is, in the substrate 70 shown in FIG. 4, the temperature of the substrate central portion 70A is 300° C. and the temperature of the substrate marginal portion 70B is 305° C. After the substrate 70 is thus set to the predetermined temperatures, a material gas is supplied into the chamber 12 to perform plasma film forming on the substrate 70.

In ordinary substrate processing, a sequence of process steps consisting of forming a film on the substrate, forming a pattern by exposure and development, and removing unnecessary portions by etching are repeatedly executed. Ideal substrate processing is a process in which a film is formed with no in-plane nonuniformity, a pattern is formed with no in-plane nonuniformity, and etching is performed with no in-plane nonuniformity. For example, in the etching step, there is a possibility of in-plane nonuniformity of the amount of etching. In such a case, the in-plane nonuniformity should be inhibited by adjusting conditions for the etching step. In some cases, however, such adjustment is impossible or difficult to perform.

In some cases, therefore, a demand is made for intentionally making nonuniform the film quality or film thickness of the film formed in the film forming step in order to absorb an in-plane nonuniformity of the amount of etching. For example, in some cases, if the amount of etching on the outer edge side of the substrate is relatively increased by etching, film forming is performed so that the thickness is increased on the substrate outer edge side.

The susceptor and the substrate processing apparatus according to the first embodiment of the present invention are capable of creating a definite temperature difference in the substrate, as described above, and are, therefore, suitable for intentionally making the film thickness or film quality of the film nonuniform. Consequently, a nonuniformity as a result of the entire process can be removed by forming a film having any desirable nonuniformity to absorb an in-plane nonuniformity other than a nonuniformity in the film forming step. That is, an in-plane nonuniformity at the end of the process can be limited.

The distribution of the film thickness of the film to be formed and the distribution of the film quality are set as desired according to conditions needed from steps other than the film forming step. For example, a film thicker (or thinner) than a film on the substrate central portion is formed on the substrate marginal portion, or a film formed on the substrate marginal portion is made harder (or softer) than a film formed on the substrate central portion.

In the case of plasma film forming, the electric field intensity is increased at the substrate central portion and is reduced at the substrate marginal portion due to the contribution of the chamber. Also, in plasma film forming, the film thickness on a portion at which the substrate temperature is low ordinarily becomes higher than that of a portion at which the substrate temperature is high. A definite temperature difference is created in the substrate by comprehensively considering factors contributing to the in-plane distribution of the film thickness or film quality to form a film having an in-plane nonuniformity which meets a demand.

The susceptor 15 and the substrate processing apparatus 10 according to the first embodiment of the present invention can be variously modified. Determination as to which portion of the film is to be made harder (or softer) or which portion is to be made thicker (or thinner) is suitably made to meet a demand from a step other than the film forming step. The susceptor and the substrate processing apparatus according to the present invention can be constructed not only as the film forming apparatus but also as an etcher. The film forming apparatus and an etcher have a commonality in being a plasma process in a vacuum.

From the viewpoint of equalization between the temperature distribution realized in the plate part 16 and the temperature distribution in the substrate 70, it is preferable that the substrate 70 be in close contact with the plate part 16. It is, therefore, preferable to maintain the substrate 70 in close contact with the plate part 16 with an electrostatic chuck provided on the plate part 16.

The change in temperature of the susceptor 15 due to contact between the substrate 70 and the susceptor 15 is small because the heat capacity of the susceptor 15 is larger than that of the substrate 70.

In the recipe, setting of a temperature difference between the first portion 16 a and the second portion 16 b may be made instead of setting of both target temperatures of the two portions.

For example, target temperatures of the first and second portions 16 a and 16 b may be set in such a manner that the target temperature of the first portion 16 a is set in the recipe and the target temperature of the second portion 16 b is defined as the result of addition of a predetermined temperature (e.g., 50° C.) to the target temperature of the first portion 16 a or subtraction of a predetermined temperature from the target temperature of the first portion 16 a.

The pattern of the heat insulating portion 16A can be changed as desired according to the required temperature distribution in the substrate. The size of the groove 16A′ and other values shown in the first embodiment is only an example and can be changed as desired. Modifications thus made can also be applied as desired to susceptors and substrate processing apparatuses according to other embodiments described below. The susceptors and substrate processing apparatuses according to the embodiments described below have a number of commonalities with those in the first embodiment and will therefore be described mainly with respect to points of difference from the first embodiment.

Second Embodiment

FIG. 6 is a plan view of the susceptor according to the second embodiment. A third portion 16 c is formed as a portion of the plate part 16. The third portion 16 c surrounds the second portion 16 b as viewed in plan. A third heater 80 for heating the third portion 16 c is embedded in the third portion 16 c. The third heater 80 is indicated by a broken line. The first heater 50, the second heater 52 and the third heater 80 are provided concentrically with each other.

An outer heat insulating portion 16B is provided in the plate part 16 on the upper surface side. The outer heat insulating portion 16B is formed by a side surface of the second portion 16 b, a side surface of the third portion 16 c distanced from the side surface of the second portion 16 b and a bottom surface connecting these side surfaces. The outer heat insulating portion 16B provides a groove 16B′ which functions as a heat insulating layer. The groove 16B′ thermally insulates the second portion 16 b and the third portion 16 c from each other on the upper surface side of the plate part 16.

With the susceptor according to the second embodiment of the present invention, the temperatures of the first portion 16 a, the second portion 16 b and the third portion 16 c can be independently set to desired temperatures. The degree of freedom of the temperature distribution in the substrate can therefore be improved in comparison with that in the susceptor according to the first embodiment in which the plate part is divided into two on the upper surface side for temperature control.

Third Embodiment

FIG. 7 is a plan view of the substrate processing apparatus according to the third embodiment. Of the chamber 12, only the side wall portion is illustrated so that the interior of the chamber 12 can be seen. In the chamber 12, the susceptor is housed. FIG. 7 shows the plate part 16. A gas exhaust part 40 is attached to a side surface of the chamber 12 for the purpose of evacuating the chamber 12 and exhausting a material gas supplied into the chamber 12. A gate valve 102 is attached to a side surface of the chamber 12 for the purpose of putting a substrate in the chamber 12 and taking out the substrate from the chamber 12. A wafer handling chamber 104 is connected to the gate valve 102.

The plate part 16 of the susceptor has a first portion 16 d, a second portion 16 e, a third portion 16 f and a fourth portion 16 g. Each of the first to forth portions 16 d, 16 e, 16 f, and 16 g is sectoral as viewed in plan. The first to forth portions 16 d, 16 e, 16 f, and 16 g are portions including the outer edge of the plate part 16. The gas exhaust part 40 and the first portion 16 d are opposed to each other as viewed in plan. The gate valve 102 and the second portion 16 e are opposed to each other as viewed in plan. Thus, the first portion 16 d is a region in the plate part 16 closer to the gas exhaust part 40, while the second portion 16 e is a region in the plate part 16 closer to the gate valve 102.

In the plate part 16, heat insulating portions 16C and 16D are formed, which are grooved portions. For the heat insulating portion 16C, a groove 16C′ is provided between the first portion 16 d and the fourth portion 16 g and between the second portion 16 e and the third portion 16 f. For the heat insulating portion 16D, a groove 16D′ is provided between the first portion 16 d and the third portion 16 f and between the second portion 16 e and the fourth portion 16 g.

For the heat insulating portions 16C and 16D, grooves forming a crisscross pattern are provided in the plate part 16. The width and depth of the grooves 16C′ and 16D′, not particularly specified, are substantially the same as those of the grooves described in the description of the first embodiment.

A first heater 110 for heating the first portion 16 d is embedded in the first portion 16 d. A second heater 112 for heating the second portion 16 e is embedded in the second portion 16 e. A third heater 114 for heating the third portion 16 f is embedded in the third portion 16 f. A fourth heater 116 for heating the fourth portion 16 g is embedded in the fourth portion 16 g. The first to fourth heaters 110, 112, 114, and 116 are individually controlled with the heater controller. Under the control of the heater controller, therefore, the first to fourth portions 16 d, 16 e, 16 f, and 16 g can have different temperatures. The first to fourth portions 16 d, 16 e, 16 f, and 16 g are thermally separated from each other on the upper surface side of the plate part 16 by the heat insulating portions 16C and 16D, thus enabling creating definite temperature differences in the substrate.

When a gas in the chamber 12 is exhausted (evacuated), the interior of the chamber 12 is not uniformly evacuated. The pressure in a place near the gas exhaust part 40 is lower than the pressure in a place remote from the gas exhaust part 40. In an area where the pressure is low, the gas stay time (the time period during which one molecule stays in plasma) is reduced. In many cases of processing in film forming apparatuses or etchers, therefore, the film forming speed is reduced in a place near the gas exhaust part 40 in the film forming apparatus, or the etching speed is reduced in a place near the gas exhaust part 40 in the etcher.

The susceptor 15 and the chamber 12 are at the same potential (ground). At the time of plasma generation, main discharge from the RF electrode 14 to the closest electrode (the plate part 16 of the susceptor 15) occurs. However, discharge from the RF electrode 14 to portions including the chambers not originally supposed to function as an electrode also occurs. From the viewpoint of preventing film forming conditions becoming uneven in the substrate plane, it is preferable that the chamber 12 surrounds the RF electrode 14, and that the distance from the RF electrode 14 are uniform with respect to all directions. In actuality, however, the distance from the RF electrode 14 to the electrodes at the ground potential and the electrode shapes are not uniform because of the gate valve 102. That is, the way of spreading of plasma in the vicinity of the gate valve 102 and the way of spreading in a place remote from the gate valve 102 are different from each other.

Thus, film forming conditions in an area near the gas exhaust part 40 and film forming conditions in an area remote from the gas exhaust part 40 are different from each other and film forming conditions in an area near the gate valve 102 and film forming conditions in an area remote from the gate valve 102 are also different from each other. That is, even between two points at the same distance from the substrate center, the film forming conditions are changed depending on the distances of the points from the gas exhaust part 40 and the gate valve 102.

Therefore, the susceptor according to the third embodiment of the present invention is designed so that the first portion 16 d opposed to the gas exhaust part 40 can be independently temperature-controlled. The temperature of the first portion 16 d is set in consideration of the specialty of film forming conditions at the first portion 16 d, thus enabling control of the film thickness and film quality of a film formed on the substrate on the first portion 16 d.

Further, the susceptor is designed so that the second portion 16 e opposed to the gate valve 102 can be independently temperature-controlled. The temperature of the second portion 16 e is set in consideration of the specialty of film forming conditions at the second portion 16 e, thus enabling control of the film thickness and film quality of a film formed on the substrate on the second portion 16 e.

In a case where the influence of the existence of the gate valve 102 on the film forming quality is small, opposing the gas exhaust part 40 and the first portion 16 d suffices and the second portion 16 e is not necessarily opposed to the gate valve 102. Also, in a case where the influence of the existence of the gas exhaust part 40 on the film forming quality is small, opposing the gate valve 102 and the second portion 16 e suffices and the first portion 16 d is not necessarily opposed to the gas exhaust part 40. The positions of the gate valve 102 and the gas exhaust part 40 are not necessarily in a symmetric relationship with each other. Also, the plate part 16 may be divided into three portions or five or more portions by heat insulating portions.

Fourth Embodiment

FIG. 8 is a plan view of the substrate processing apparatus according to the fourth embodiment. The first portion 16 a, the second portion 16 b, and heat insulating portion 16A and the outer heat insulating portion 16B are provided in the same way as those of the plate part 16 in the second embodiment (FIG. 6). In the fourth embodiment of the present invention, the third portion 16 c in the second embodiment is divided into four. That is, as shown in FIG. 8, four third portions 16 h, 16 i, 16 j, and 16 k are provided as portions of the plate part 16. The four third portions 161 h, 16 i, 16 j, and 16 k as a whole surround the second portion 16 b as viewed in plan. The third portion 16 h is opposed to the gas exhaust part 40. The third portion 16 j is opposed to the gate valve 102.

A third heater 124 for heating the third portion 16 h is embedded in the third portion 16 h. A third heater 126 for heating the third portion 16 i is embedded in the third portion 16 i. A third heater 128 for heating the third portion 16 j is embedded in the third portion 16 j. A third heater 130 for heating the third portion 16 k is embedded in the third portion 16 k. Thus, one third heater is provided in each of the plurality of third portions. The four third heaters 124, 126, 128, and 130 are individually controlled by the heater controller. The four third portions 16 h, 16 i, 16 j, and 16 k can therefore be controlled by the heater controller to have different temperatures.

The outer heat insulating portion 16B, which is a grooved portion, is formed in the plate part. The outer heat insulating portion 16B thermally insulates the second portion 16 b and the plurality of third portions 16 h, 16 i, 16 j, and 16 k from each other on the upper surface side of the plate part. Further, outer-edge-side heat insulating portions 16G, 16H, 16I, and 16J, which are grooved portions, are formed in the plate part. The outer-edge-side heat insulating portions 16G, 16H, 16I, and 16J thermally insulate the plurality of third portions from each other on the upper surface side of the plate part. The first portion 16 a, the second portion 16 b, and the plurality of third portions 16 h, 16 i, 16 j, and 16 k are thermally separated from each other on the upper surface side of the plate part by the heat insulating portion 16A, the outer heat insulating portion 16B and the outer-edge-side heat insulating portions 16G, 16H, 16I, and 16J, thus enabling creating definite temperature differences in the substrate.

In some cases, the influence of the existence of the gas exhaust part 40 on film forming conditions are particularly large at an edge portion of the substrate near the gas exhaust part 40 and is small at a central portion of the substrate. In the fourth embodiment of the present invention, therefore, independent temperature control of the third portion 16 h opposed to the gas exhaust part 40 at an outer edge portion of the plate part is enabled. The temperature of the third portion 16 h is set in consideration of the specialty of film forming conditions at the third portion 16 h, thus enabling control of the film thickness and film quality of a film formed on the substrate on the third portion 16 h.

Also, in some cases, the influence of the existence of the gate valve 102 on film forming conditions are particularly large at an edge portion of the substrate near the gate valve 102 and is small at a central portion of the substrate. In the fourth embodiment of the present invention, therefore, independent temperature control of the third portion 16 j opposed to the gate valve 102 at an outer edge portion of the plate part is enabled. The temperature of the third portion 16 j is set in consideration of the specialty of film forming conditions at the third portion 16 j, thus enabling control of the film thickness and film quality of a film formed on the substrate on the third portion 16 j.

Since the first heater 50, the second heater 52 and the plurality of third heaters 124, 126, 128, and 130 are provided concentrically with each other, temperature settings can be made in consideration of changes in film forming conditions dependent on the distance from the center of the plate part (center-edge relationship) in the same way as in the susceptor in the second embodiment. That is, with the susceptor and the substrate processing apparatus according to the fourth embodiment of the present invention, a film thickness distribution and a film quality distribution selected as desired can be realized while correcting the center-edge relationship, the influence of the existence of the gas exhaust part 40 and the influence of the existence of the gate valve 102.

The number of third portions is not limited to four. A plurality of third portions may be used. If the number of portions which can be independently temperature-controlled is increased, for example, by increasing the number of grooved portions and freely changing the shapes of grooved portions, a complicated film thickness distribution or film quality distribution can be realized.

Fifth Embodiment

FIG. 9 is a sectional view of a susceptor and other members according to the fifth embodiment. This susceptor is similar to the susceptor according to the second embodiment

(FIG. 6). However, the widths of the grooves 16A′ and 16B′ formed in the heat insulating portion 16A and the outer heat insulating portion 16B are larger than those in the second embodiment. Also, a first closing part 160 is provided on the first portion 16 a. The first closing part 160 closes part of the groove 16A′ in the grooved portion without contacting the second portion 16 b. The shape (planar shape) of the first closing part 160 as viewed in plan is circular. A second closing part 162 is provided on the second portion I 6 b. The second closing part 162 closes part of the groove 16A′ in the grooved portion and part of the groove 16B′ without contacting the first portion 16 a and the first closing part 160. The planer shape of the second closing part 162 is annular, surrounding the first closing part 160.

A third closing part 164 is provided on the third portion 16 c. The third closing part 164 closes part of the groove 16B′ without contacting the second portion 16 b and the second closing part 162. The planer shape of the third closing part 164 is annular, surrounding the second closing part 162. The substrate 70 to be processed is placed on the first closing part 160, the second closing part 162 and the third closing part 164. The material of the first to third closing parts 160, 162, and 164 is not particularly specified, if it does not largely impede plasma discharge. The material may be, for example, a ceramic or Al.

The effect of thermally insulating the first portion 16 a and the second portion 16 b from each other and the effect of thermally insulating the second portion 16 b and the third portion 16 e from each other can be improved by increasing the width (x3) of the groove 16A′ and the width (x4) of the groove 16B′. However, if the substrate is heated while being directly placed on the plate part having the width (x3) of the groove 16A′ and the width (x4) of the groove 16B′ increased, then the substrate temperature is not sufficiently increased at the positions right above the grooves 16A′ and 16B′. That is, unintended temperature variation occurs.

To prevent this, the first to third closing parts 160, 162, and 164 are provided. The first closing part 160 and the second closing part 162 close part of the groove 16A′. Therefore the distance (xl) between the first closing part 160 and the second closing part 162 is smaller than the width (x3) of the groove 16A′. The second closing part 162 and the third closing part 164 close part of the groove 16B′. Therefore the distance (x2) between the second closing part 162 and the third closing part 164 is smaller than the width (x4) of the groove 16B′. Consequently, unintended temperature variation can be limited in comparison with the case where the substrate is directly placed on the plate part 16.

It is preferable to change the number of closing parts according to the number of grooves formed in the plate part. For example, in a case where only the groove 16A′ is formed in the plate part, the third closing part 164 is not provided. Sixth Embodiment

FIG. 10 is a sectional view of a susceptor according to the sixth embodiment. The first portion 16 a, the second portion 16 b and the third portion 16 c are separate parts. In other words, the third portion 16 c can be detached from the second portion 16 b. The second portion 16 b can be detached from the first portion 16 a. The second portion 16 b and the third portion 16 c are annular parts as viewed in plan. A projection 160 is provided on a side surface of the first portion 16 a, and the second portion 16 b is put on this projection 160. A projection 162 is provided on a side surface of the second portion 16 b, and the third portion 16 c is put on this projection 162.

The grooved portion (heat insulating portion 16A) is formed by the side surface of the first portion 16 a, an upper surface of the projection 160, and a side surface of the second portion 16 b. The outer heat insulating portion 16B is formed by the side surface of the second portion 16 b, an upper surface of the projection 162 and a side surface of the third portion 16 c.

As is apparent from FIG. 10, the deep groove 16A′ can be provided by providing the projection 160 at the lower end of the side surface of the first portion 16 a and by reducing the thickness of the projection 160. The deep groove 16B′ can be provided by providing the projection 162 at the lower end of the side surface of the second portion 16 b and by reducing the thickness of the projection 162. If the groove is made deep in the susceptor in the first embodiment, there is an apprehension that the strength of the susceptor is considerably reduced. However, the susceptor according to the sixth embodiment of the present invention is capable of securing the strength while making the groove deep, since it is of an assembly type.

Seventh Embodiment

FIG. 11 is a sectional view of a susceptor and other members according to the seventh embodiment. This susceptor has a cooling member 200 attached to the plate part 16, and a cooling member 202 attached to the slide shaft 18. The cooling members 200 and 202 are not particularly specified, if a well-known cooling method is used. The cooling member 200 is attached right below the grooved portions of the plate part 16 (heat insulating portion 16A and outer heat insulating portion 16B). The degrees of cooling by the cooling members 200 and 202 are controlled by the heater controller.

For example, when plasma is caused to arise at 1 kW, the temperature of the susceptor is increased to a certain degree by RF energy. In some cases, this temperature rise makes it difficult to realize a low-temperature process. In the susceptor according to the seventh embodiment of the present invention, therefore, the susceptor is cooled with the cooling members 200 and 202 to limit the rise in temperature of the susceptor, thereby enabling a low-temperature process to be realized.

On the upper surface side of the plate part, the first portion 16 a, the second portion 16 b and the third portion 16 c are thermally separated from each other. On the lower surface side of the plate part, however, these portions are not thermally separated from each other. Therefore, heat transfer between the first to third portions 16 a, 16 b, and 16 c occurs mainly on the lower surface side of the plate part. In the susceptor according to the seventh embodiment of the present invention, the cooling member 200 is provided on the lower surface side of the plate part 16 to limit this heat transfer. More specifically, the cooling member 200 is provided right below the grooved portions (heat insulating portion 16A and outer heat insulating portion 16B), thereby enabling limiting of heat transfer between the first portion 16 a and the second portion 16 b and heat transfer between the second portion 16 b and the third portion 16 c. The cooling member 200 may be embedded in the plate part 16, and the cooling member 202 may be embedded in the slide shaft 18.

Eighth Embodiment

FIG. 12 is a sectional view of a susceptor according to the eighth embodiment. In the first to seventh embodiments, the grooved portion is provided in the plate part on the upper surface side as a heat insulating portion for thermally insulating the first portion and the second portion of the plate part from each other. However, a heat insulating portion in the eighth embodiment is a cooling device 210 provided in the plate part 16. The degree of cooling with the cooling device 210 is controlled by the heater controller. A first heater 50 and a second heater 52 are operated while the cooling device 210 is operated. Then the first portion 16 a and the second portion 16 b are thermally insulated from each other by cooling with the cooling device 210. It is preferable to thermally insulate the first portion 16 a and the second portion 16 b particularly on the upper surface side of the plate part 16. Thermal insulation of the first portion 16 a and the second portion 16 b enables creating a definite temperature difference in the substrate without providing any groove. A suitable combination of the embodiments described above may be made and used.

According to the present invention, certain different regions in the susceptor are thermally insulated from each other by a heat insulating portion, thus enabling creating a definite temperature difference.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described. 

What is claimed is:
 1. A susceptor comprising: a plate part; a first heater for heating a first portion of the plate part; a second heater for heating a second portion of the plate part; and a heat insulating portion for thermally insulating the first portion and the second portion from each other on an upper surface side of the plate part.
 2. The susceptor according to claim 1, wherein the heat insulating portion is a grooved portion provided in the plate part on the upper surface side.
 3. The susceptor according to claim 1, wherein the second portion surrounds the first portion as viewed in plan.
 4. The susceptor according to claim 3, further comprising: a third portion formed as a portion of the plate part, the third portion surrounding the second portion as viewed in plan; a third heater for heating the third portion; and an outer heat insulating portion for thermally insulating the second portion and the third portion from each other on the upper surface side of the plate part.
 5. The susceptor according to claim 1, wherein each of the first portion and the second portion is formed in sectoral form as viewed in plan.
 6. The susceptor according to claim 1, wherein the first portion is a portion including an outer edge of the plate part, and the second portion is a portion including an outer edge of the plate part.
 7. The susceptor according to claim 3, further comprising: a plurality of third portions formed as part of the plate part, the third portions as a whole surrounding the second portion as viewed in plan; a plurality of third heaters provided in the plurality of third portions in a one-to-one relationship; an outer heat insulating portion for thermally insulating the second portion and the plurality of third portions from each other on the upper surface side of the plate part; and outer-edge-side heat insulating portions for thermally insulating the plurality of third portions from each other on the upper surface side of the plate part.
 8. The susceptor according to claim 2, further comprising: a first closing part provided on the first portion to close part of a groove in the grooved portion without contacting the second portion; and a second closing part provided on the second portion to close part of a groove in the grooved portion without contacting the first portion and the first closing part.
 9. The susceptor according to claim 2, wherein the first portion and the second portion are separate parts; a projection is provided on a side surface of the first portion, the second portion being put on the projection; and the grooved portion is formed by a side surface of the first portion, an upper surface of the projection and a side surface of the second portion.
 10. The susceptor according to claim 1, further comprising a cooling member attached to the plate part.
 11. The susceptor according to claim 2, further comprising a cooling member attached to the plate part, wherein the cooling member is attached to the plate part right below the grooved portion.
 12. The susceptor according to claim 1, further comprising an electrostatic chuck.
 13. The susceptor according to claim 1, wherein the heat insulating portion is a cooling device provided in the plate part.
 14. A substrate processing apparatus comprising: a susceptor having a plate part, a first heater for heating a first portion of the plate part, a second heater for heating a second portion of the plate part, and a heat insulating portion for thermally insulating the first portion and the second portion from each other on an upper surface side of the plate part; a chamber in which the susceptor is housed; and an gas exhaust part attached to a side surface of the chamber, wherein the first portion is a portion including an outer edge of the plate part; the second portion is a portion including an outer edge of the plate part; and the gas exhaust part and the first portion are opposed to each other as viewed in plan.
 15. A substrate processing apparatus comprising: a susceptor having a plate part, a first heater for heating a first portion of the plate part, a second heater for heating a second portion of the plate part, and a heat insulating portion for thermally insulating the first portion and the second portion from each other on an upper surface side of the plate part; a chamber in which the susceptor is housed; and a gate valve attached to a side surface of the chamber, wherein the first portion is a portion including an outer edge of the plate part; the second portion is a portion including an outer edge of the plate part; and the gate valve and the second portion are opposed to each other as viewed in plan. 